Secondhand smoke levels were assessed among a convenience sample of 15 public venues in Amman, Jordan, during Ramadan. PM2.5 measurements were taken inside each venue pre- and post-'iftar', when daily smoking abstinence can be broken at sundown. Cigarette smoking was observed in all venues post-iftar, and the median PM(2.5) level among the 15 venues (285 µg/m(3)) was significantly higher than the pre-iftar level (11 µg/m(3); P < 0.001). Post-iftar PM(2.5) levels exceeded the World Health Organization standard for particulate pollution by 5-20-fold. To protect public health in Jordan, smoke-free legislation should be enforced at all times of day, and all days of the year.